L. Hyvonen, et al., "Effects of Temperature and Concentration on the Relative Sweetness of Fructose, Glucose and Xylitol", Lebensm-Wiss. u.-Technol., 10:316-320 (1977), reported that temperature has a noticeable effect on the relative sweetness of fructose, i.e., that the relative sweetness of fructose varies inversely with temperature over the range of 5.degree. C. to 50.degree. C. in other words, Hyvonen reported that fructose is sweeter, by relative sweetness, at 5.degree. C. than at 50.degree. C. Because the concentration of the .beta.-D-fructopyranose anomer in a solution also varies inversely with temperature, it has been generally inferred by those in the art that .beta.-D-fructopyranose is the sweetest anomer of fructose in solution and that a fructose solution thus becomes sweeter as one decreases the temperature thereof. See J. Dziezak, "Crystalline Fructose: A Breakthrough in Corn Sweetener Process Technology", Food Technology, Vol. 41, pp. 66, 67 and 72 (January 1987).
Dziezak also discloses that the sweetness of a fructose solution increases as the pH is decreased. However, Hyvonen, et al., "The Relative Sweetness of Fructose, Glucose, and Xylitol in Acid Solutions at Different Temperatures", Lebensm.-Wiss. u.-Technol. 11:11-14 (1978) reports that the relative sweetness of fructose was reduced by acids at room temperature and, at page 14, Table 3, that citric, malic, and phosphoric each reduced the relative sweetness at room temperature to approximately the same degree at approximately the same pH.